Driving gear for the bucket chains of dredgers



Get. 16, 1928.

1,687,845 H. A. J. DE B. NACHENIUS DRIVING GEAR FOR THE BUCKET CHAINS OF DhEDGERS Filed Aug. 5, 1 926 2 Sheets-Sheet 1 O 0 29 F I6. I.

WVE/VfO/i #6? Mali-9444 AKQc/ /E/V/as H. A. J. DE B. NACHENIUS DRIVING GEAR FOR THE BUCKET CHAINS OF DREDGERS Filed Aug. 5, 1926 2 Sheets-Sheet 2 Patented Oct. 16, 1928.

HENRI ARNOLD JOHANNES DE BIJ'LL NACHENIUS, OF HAABLEM, NETHERLANDS.

DRIVING GEAR FOR THE BUCKET CHAINS OF DREDGEBS...

Application filed August 5,

The ordinary driving bucket gear for the five or six sided drum, the so-called top tumbler,

over which the chainruns,

mechanism for driving Dredgers, which have to fer from the rapid wear bler and of the bucket ordinary pulling forces crating forces being so 0 and a gear wheel the tumbler shaft.

do heavy work,.suf-

and tear of the tumchain, owing to the and also the accelonsiderable, that the material used in the construction is overloaded. pins tends to increase hloreover,-the wear and tear of the the pitch of the chain,

whereby the parts are shifted relatively to one another and the wear is still further accelerated.

The object of the invention is to meet these disadvantages by the useother than the normal tumbler. In addition of a construction construction with a to attaining this obiect, the invention realizes still other constructional advantages,

which will be eX- plained after some embodiments of the inv vention have been descrlbed.

Figures 1 and 2 of the accompanying drawless diagrammatlcally ing illustrate more or two embodlments of a dr ance with the inventlon.

iving gear in accord- Figure 3 is a SQGLlOll of a detail, on an enlarged scale.

Figure 1 shows a driving aggregate.

Figure 5 18 a detail of the driving gear'as per Figure 1. e

' Figures 1 and 2 tion of a bucket chain, carries a bucket. In 0th fewer buckets, but the i plied thereto as well. composed of buckets 8, interconnected. by pins The bucket illustrate the upper porof whicheach link er dredgers there are nvention can be-apchain is which are pivotally 9. It runs over a top tumbler in the form of a roller 10, in the manner in which it is known to at the lower end of further supported in the chain over a roller ladder, and 1t 1s pass a bucketthe usual manner by guide rollers 11,'the brackets of which are mounted on the ladder 12.

The bucket-chain is driven by three equal driving aggregates, which are-independent of one another[ Each comprises, as shown in driving aggregate Figuresl and 2, an

electric motor 13, a motor pinion 14:, a transmission gear 15, a trans 'drivmg gear 17 and a mission pinion 16, a dIlVlIlg pinion 18.

. (Figure 3) may on purpose be at the passing of the 1926, Serial N0.'127,387, and in the Netherlands June 30, 1926.

The latter cooperateswith teeth 19, formed in the bucket backs. Consequently, the series of teeth 19 forms an endless rack. The m0- tors and transmission gearings are mounted in a bracket, which is secured to the ladder 12 at the outside thereof. The driving shafts 21- are rotatable in bearing blocks also mounted to the ladder.

, Also. with this driving mechanism the pitch of the bucket chain will increase in the long run, owing to wear of the ins. To prevent the teeth 19 of the chain rom running, as a consequence of the said fact, on the teeth of the driving pinions, the pitch between the tooth flanks 22 and 23 made smaller than the normal pitch of the teeth of the chain, such as exists, for instance, between the tooth flanks .24 and 25. According as the pitch of the links increases owing to wear and tear, the magnitude of this intentionally made error diminishes, Therefore, although itch 22-23 over the pinion the flank '23 wi l not'at once catch a tooth of the pinion 18, this does not involve a seriousdisadvantage, since it is here a matter of an interval of' secondatthe most. In this connection it may be observed that; the driving aggregates are so spaced, that the discontinuitfes in the" driving force do not occur simultaneously. 1 There is an excess of driving force available, "so that the momentary disengagement of a drivingpinion does not matter. 4 Prov1s:.on may even bemade of such a great number of small aggregates,

Asout of order, so that that some of them maybe thrown out. suming a motor tobe the driving gear of its aggregate would have to be dragged, the chain may bump on the tooth heads of the pinion 18 concerned, and

be lifted, whereas the remaining aggregates remain in normal operation.

In order that the bucket chain may not be lifted off the driving pinions 18 under'the influence of the tooth pressure, the flanks of the teeth-19 aredisposed at right angles, 7

or approximately at right angles, to the pitch line.

Itis essential that the flank 23 of each.

link be overtaken at a suitable speed by the coacting tooth of the pinion 18, but it is also desirable to prevent the pinion from suddenly racing when disengaging a flank22.

Such racing would have a destructive influence on the edges of the teeth. For this reason the driving gear 17 is provided with a loose gear rim (Figure 5), which through springs 26 transmits the driving force of the pinion 14 (Figure 4) or 16 (F ig'ures 1 and 2) to a disk 27 acting as a flywheel and secured to the shaft 21'. The inertia of this disk prevents the pinion 18 from suddenly racing when disengaging the flank 22, but thereafter the disk and the pinion are nevertheless accelerated a little under the influence of the springs, so that the flank 23 is soon overtaken. The spring tension and the mass of the flywheel should be so. chosen, that a smooth running and a low average tooth pressure are obtained. As the differences in dimensions, which in devices of this character are unavoidable in the long run, are distributed, as far as their effect is concerned, over a plurality of driving gears, irregularities aremuch less serious than withprovided with a driven tumbler.

. In accordance with Figure 1, the ladder 12 isrotatable about the ladder suspension shaft 28 and is provided with an upwardly pro-. jecting portion. 29 supporting the shaft of the top roller 10. The upper part of the.

chain will therefore always have the same formiirrespective of whether the ladder is in its lowermost position as shown, or is hoisted. The portion of the bucket-chain between the top roller 10. and the uppermost driving aggregate is always kept suitably taut by the gravitypull of the lower part. According to Figure 2, the ladder is suspended from a ladder suspension shaft 30, whereas the top; roller 10 is mounted with its bearing blocks on the main frame 31.

With this construction the uppermost guide roller 11 is solocated,that also in a higher position of the ladder a sufficient part of the weight of the chain will counteract forces that might tend to move the chain away from the guide rollers and the driving pinions. The chain teeth wear down relatively slowly, because their number is great with respect to the number of teeth of the pinions.

, Abstracting from accidental details of the illustrated embodiments, it will be seen that the invention is broadly embodied in a buck- ;et-chain, the stretched part (or a portion,

the radius of curvature of which exceeds that of the bight over the top roller'or tumbler) of which is acted upon by a driving gear, or, preferably, by aplurality of (i. e. at least two) independent driving aggregates which preferably are mounted on the ladder. The principle of the invention does not depend upon the employment of long links, or, for instance, upon the provision of one central series of teeth in the chain, or upon the form, of the chain links and their connection with the buckets. The chain could very well be guided to form a slight curve,

dredgers.

whereby the force, which counteracts the tendency to lift the chain, is 1ncreased. The use. of a plurality of'drivmg aggregates,

which'act upon the more or less stretcheduniform and the tensional stresses are reduced to a minimum where the curvature is maximum. But also the super-structure of the dredger may be much simplified. The main frame can be made lighter .and less complicated, owing to the absence of the heavy driving mechanism and. of the erection auxiliaries. The smaller aggregates. substitutedtherefor can easilybe mounted on one sideor on both sidesof the ladder. Repairs of these small aggregates can easily be carried out, because said aggregates are to a certain extent independent of the bucket-chain. Quite a number of simple constructions exist for quickly bringing thedriving aggregates out of engagement with the chain, for instance, when a driving pinion is tem is especially suitable for electric drive, but it will be understood that belt drive could be used as well. v

A ladder projecting above the ladder suspension shaft and provided at that, project ing end with a tumbler or a roller, can be suitably used only in connection with the driving gear inaccordance with the invention, because at the top there need be no driving gear. at all. Consequently, this construction represents a. further development of the invention.

formed as racks,

two successive links is shorter than normal,

is a sub-invention.

What I claim is 1. An endless: bucket chain including links of a bucket rack.

2. An endless bucket chain including links formed as racks, the pitch between the final to be renewed- The sys- The embodiment, in which the links are I so that the pitch between tooth of one bucket rack and the initial tooth ofthe next bucket rack being normally less than the pitch of theremaining teeth of a bucket rack, and a plurality of independent driving aggi egatescooperating with the teeth of the rack.

3. An endless bucket chain including links formed as racks, the pitch between the final tooth of one bucket rack and the initial tooth ofthe next bucket being normally less than the pitch of the rack, and means cooperating with the of the remaining teeth of a bucket rack, a plurality of independent driv- I ing aggregates cooperating with the teeth driving aggregates to compensate for the reduced pitch of the adjacent teeth of the bucket racks.

4. An endless bucket chain including links 5 formed as racks, the

pitch between the final tooth of one bucket rack and the initial tooth of the next buc less than the pitch ket rack being normally of the remaining teeth of the-bucket rack, a plurality of independent driving aggregates cooperating with the 10 teeth of the racks, and a cooperating fly wheel including spring accelerating means to compensate for the shorter pitch.

In testimony whereof I aflix my signature;v

. HENRI ARNOLD JOHANNES dc BULL NACHl-ZNIUS. 

